Recently, a database management system is used in an embedded device such as a digital appliance, which includes a large-size storage. In the embedded device, although a capacity of main memory is increased, the capacity does not extend beyond several kilobytes to several megabytes, and it is necessary to perform processing within a restricted resource. Therefore, registration performance and update performance are not very high.
For example, disclosed is a technology relating to a DB file; a temporary write file in which update data is temporarily stored in units of pages; and shadow paging in which a map table is utilized to record a list of update pages in the temporary write file.